---
title:  Keeping the Cache in Sync with Outside Data Sources
---

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Keep your distributed cache in sync with an outside data source by programming and installing application plug-ins for your region.

-   **[Overview of Outside Data Sources](chapter_overview.html)**

    <%=vars.product_name_long%> has application plug-ins to read data into the cache and write it out.

-   **[Configuring Database Connections Using JNDI](configuring_db_connections_using_JNDI.html)**.

    Use JNDI to maintain a connection pool that includes outside data sources.

-   **[How Data Loaders Work](how_data_loaders_work.html)**

    By default, a region has no data loader defined. Plug an application-defined loader into any region by setting the region attribute cache-loader on the members that host data for the region.

-   **[Implement a Data Loader](implementing_data_loaders.html)**

    Program a data loader and configure your region to use it.


